Veronica Augustyn
Texas Materials Institute
The University of Texas at Austin

High-rate electrochemical energy storage with pseudocapacitive oxides

Location: EB1 Room 1011

Friday, January 23rd 2015 - 11:00 am

A long-standing challenge for electrochemical energy storage has been to achieve both high energy and high power densities in the same device. This inability arises from the fundamental differences between storing energy within the solid state, as in batteries, as opposed to the surface, as in capacitors. Bridging the gap between energy and power is the motivation for the development of new high-energy and high-power energy storage materials. In this seminar, I will describe how such materials are possible with pseudocapacitance in transition metal oxides, whereby charge storage occurs via rapid redox reactions. Pseudocapacitive behavior can be readily identified by examining key electrochemical features. Using these features as guidelines, two different materials will be discussed. First, Nb2O5, which exhibits "intrinsic" intercalation pseudocapacitance, and then, TiO2 nanosheets, which exhibit "extrinsic" redox pseudocapacitance. Finally, I will describe how pseudocapacitive features before the onset of the oxygen evolution reaction are useful in understanding the electrocatalytic behavior of layered transition metal oxides.

North Carolina State University